Turbine with tube arrangement and method of preventing detachment of a fluid flow

ABSTRACT

Turbine system including a turbine and a tubular arrangement having an exit opening. The tubular arrangement is arranged on a downstream side of the turbine. At least one flow controlling device at least partially prevents a fluid flow through the tubular arrangement from becoming detached from the tubular arrangement. The at least one flow controlling device is positioned within the fluid flow and in an area of the exit opening. The turbine system is configured to operate efficiently in an environment wherein at least an upper edge of the exit opening is arranged above a downstream liquid level.

CROSS-REFERENCE TO RELATED APPLICATIONS

The instant application is a division of U.S. application Ser. No.10/848,381 (now U.S. Pat. No. 7,284,948), filed May 19, 2004, and acontinuation of International Application No. PCT/EP03/02777 filed onMar. 18, 2003 and published as International Publication WO 03/085255 onOct. 16, 2003, the disclosures of each which are hereby expresslyincorporated by reference hereto in its entirety. The instantapplication also claims priority under 35 U.S.C. §119 of AustrianApplication No. A 549/2002 filed on Apr. 10, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a turbine or a turbine-generator unithaving a tube connected to the turbine downstream for operation with aliquid level which is low or absent downstream of the turbine, and aturbine-generator module comprising a number of turbine-generator unitsof this type. The invention also relates to the use of a turbine orturbine-generator unit of this type and a method for operating a turbineor turbine-generator unit through which liquid can flow, a method foroperating a plant for generating electrical energy, a method forconverting a structure for retaining a liquid medium into a device forgenerating electrical energy, and a method for generating electricalenergy at a structure for retaining a liquid medium.

2. Description of the Prior Art

A tube, generally a suction tube, of a turbine or turbine-generator unitin practice always has to open out into the tailwater and must neverspray into the open air, since if it does so, particularly in the caseof suction tubes with a considerable divergence, the discharge jet canbecome detached from the suction tube, which reduces the hydraulicefficiency and therefore also the plant efficiency of aturbine-generator unit of this type considerably, to an economicallyunacceptable level. For this reason, attempts should be made to avoidsuch a situation in practice.

For design reasons, and in this context in particular, when existing damstructures are being used, it is, however, sometimes not possible tosatisfy this condition, since the tailwater level is too low from theoutset. Therefore, in a plant of this type, it has hitherto beenimpossible to install an efficient turbine or turbine-generator unit forgenerating electrical energy.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a turbine or turbine-generatorunit which can be operated with high hydraulic efficiency even if itstube connected downstream does not open out into the tailwater or doesso only partially and which can nevertheless be constructed veryefficiently and with a simple design.

According to the invention, there is provided an arrangement which canat least partially prevent the flow from becoming detached from thetube. An arrangement of this type prevents the flow from becomingdetached in the tube of the turbine or turbine-generator unit which isconnected to the turbine and thereby prevents a drop in the hydraulicefficiency. The plant efficiency, which is composed of the mechanicalefficiency, which is substantially determined by friction losses in thebearings, the hydraulic efficiency, which is substantially determined bythe turbine efficiency, and the electrical efficiency of the generator,can, as a result, likewise be kept at a high level. This is extremelyimportant for economic reasons.

Therefore, a turbine or turbine-generator units of this type can be usedeven if, for example, for design reasons, it is not possible for thetube to open out completely into the tailwater, as has hitherto beenrequired. This makes it possible to retrofit even existing daminstallations with a liquid level which is low or absent downstream ofthe turbine with turbine-generator units for the generation ofelectrical energy without the design of the dam installation itselfbeing altered.

The inventive concept can be used very particularly advantageously forturbines with suction tubes, since in practice, mostly for efficiencyreasons, the tube used is generally a suction tube, and in this case thephenomenon whereby the flow through the divergent suction tube becomesdetached, in particular in the case of strongly divergent suction tubes,leads to problems particularly frequently.

For space reasons, it is often expedient for the turbine to be designedwith axes of rotation which are substantially horizontal or inclinedwith respect to this horizontal, in which case the turbineadvantageously has a turbine rotor, on which a plurality of turbineblades which are arranged rigidly on the turbine rotor are arranged,resulting in an arrangement which is particularly simple to implement.

A very simple and, at the same time, very effective arrangement forpreventing the flow of liquid from becoming detached is a flow body. Aflow body of this type is simple to produce and is very simple toimplement in design terms.

The efficiency of the flow body can be increased if it is arranged inthe tube, preferably in the region of the downstream end of the tube.The phenomenon of the flow becoming detached generally starts at the endof the tube, and consequently the flow body is advantageously also usedat that location.

A very particularly simple embodiment without any loss of efficiencyresults if the flow body is designed as at least one rib which can bearranged substantially horizontally, vertically or also with any desiredinclination. A rib, i.e., in principle a simple piece of sheet metal,can be produced and installed particularly easily and effectively.

If a plurality of ribs are used, the distance between two ribs can becalculated substantially according to the formula v≧√{square root over(g.h)}, where “v” is the flow velocity, “g” is the acceleration due togravity, and “h” is the distance between two ribs. This likewise resultsin a simple method for predetermining the number of ribs required.

To increase the effectiveness of the flow body still further, it is alsoconceivable for a rib to be arranged inclined with respect to the flow,so that a local nozzle effect, which makes it significantly moredifficult for the flow to become detached, is produced in part of thesuction tube.

A further highly advantageous embodiment of a flow body is a pear-shapedbody which is arranged concentrically in the tube and is held in thetube by a number of supporting blades. A body of this type is likewisesimple to produce and is favorable and simple in design terms toimplement.

The most simple design, making it highly advantageous, is an arrangementin which the tube, in the operating position, in the state in whichthere is no medium flowing through it, at least partially opens out intothe open air, so that there is no need for any expensive linings orsimilar structures.

The advantage of a turbine according to the, invention becomesparticularly apparent in installations where the tube, in the state inwhich there is no medium flowing through it, in its operating position,with respect to the tailwater level, projects entirely into the openair, although intermediate ranges of between approximately 25%,approximately 50% and approximately 75% coverage are also conceivable.Dam installations of this type can now, for the first time, be used togenerate electrical energy without any restriction to the hydraulicefficiency.

A turbine or turbine-generator unit according to the invention isadvantageously used in a turbine-generator module, comprising aplurality of turbine-generator units which are arranged next to and/orabove one another and are connected to one another, for operation with aliquid level which is low or absent downstream of the turbine-generatorunit. In a particular design variant, the tubes of the turbine-generatorunits which are arranged next to one another in a row at least in partopen out into the open air, and the arrangement for preventing the flowfrom becoming detached acts on all the tubes in this row.

For design reasons and/or cost reasons, it is also conceivable toprovide a single tube for a number of turbine-generator units of theturbine-generator module. Therefore, under certain circumstances, theturbine-generator module can be more compact, more lightweight and ofsimpler design.

A turbine, turbine-generator unit or turbine-generator module accordingto the invention can very particularly advantageously be used in an atleast partially existing dam installation with a tailwater level whichis low or absent, since in this case no design changes or onlyinsignificant design changes have to be made to the dam installation forthe concept to be usable.

The turbine-generator module is particularly advantageously operated forgeneration of electrical energy between two stationary structures of thedam installation, so that the existing structures can be optimallyutilized.

The inventive concept of maintaining the flow in the tube of the turbineallows such a turbine to be operated as a result of the flow of theliquid immediately downstream of the tube, at least in sections, beingmaintained above the tailwater level, so that the hydraulic efficiencyof the turbine which is required for energy generation is achieved. Thismakes it possible for the flow to be maintained in a very wide rangefrom approximately 10%, approximately 50%, approximately 100%,approximately 300% and even more than approximately 500% above theliquid level.

A turbine-generator unit according to the invention or a plant forgenerating electrical energy having at least one turbine-generator unitor at least one turbine-generator module can, for the first time, beoperated particularly favorably without any loss of efficiency even ifthe liquid level at a distance downstream of the tube is kept in a rangefrom below the bottom edge of the tube to at most directly below the topedge of the tube. In this way, the flow in the tube is at leastpartially prevented from becoming detached.

With a turbine, turbine-generator unit or turbine-generator moduleaccording to the invention, it is for the first time possible for astructure which retains a liquid medium to be converted in aparticularly simple and advantageous way (and without losses ofefficiency) into a device for generating electrical energy. The systemcan account for the level of the medium downstream of the structure andthe level of the medium upstream of the structure, which is higher thanthe level of the medium downstream of the structure. At least oneturbine-generator module can be produced to operate in this environment.The design and efficiency of the turbines and/or generators can bematched to the levels which have been determined, and the flow of themedium immediately downstream of the tube, at least in sections, can bemaintained above the level of the medium downstream of the structure.Using such a system, the flow can be at least partially prevented frombecoming detached from the tube, so that the hydraulic efficiency of theturbine which is required for energy generation is achieved.

The same is true of a method for generating electrical energy at astructure for retaining a liquid medium, the medium having a level whichis low or absent downstream of the structure.

The invention also provides for a turbine system which comprises aturbine and a tubular arrangement comprising an opening region. Thetubular arrangement is connected to a downstream side of the turbine. Aflow arrangement at least partially prevents a fluid flow from becomingdetached from the tubular arrangement. The flow arrangement ispositioned within the fluid flow and in an area of the opening region.The turbine system is configured to operate at least one of in anenvironment wherein there is a low liquid level downstream of theturbine and in an environment wherein there is no liquid leveldownstream of the turbine.

The tubular arrangement may be a suction tube. An axis of rotation ofthe turbine may be arranged one of on a plane which is substantiallyhorizontal and arranged on a plane which is inclined with respect to ahorizontal plane. The turbine may comprise a turbine rotor and aplurality of turbine blades rigidly arranged on the turbine rotor. Theflow arrangement may comprise a flow body. The flow body may be arrangedin an area of a downstream end of the tubular arrangement. The flowarrangement may comprise at least one rib. The at least one rib may bearranged substantially horizontally. The flow arrangement may compriseat least one flow body that is arranged substantially vertically. Theflow arrangement may comprises at least one flow body that is arrangedsubstantially inclined with respect to one of a horizontal plane and avertical plane.

The flow arrangement may comprise two ribs arranged at a distance fromone another, whereby the distance between the two ribs is substantiallycalculated using a formula v≧√{square root over (g.h)}, wherein “v” is aflow velocity, “g” is an acceleration due to gravity, and “h” is thedistance between two ribs.

The flow arrangement may comprise at least one rib that is arranged atan angle that is inclined with respect to the fluid flow.

The flow arrangement may comprise at least one pear-shaped body arrangedconcentrically in the tubular arrangement. The at least one pear-shapedbody is supported in the tubular arrangement by a plurality of supportblades.

The tubular arrangement at least partially opens out into open air.

The turbine system may be arranged in an operating position relative toa tailwater level such that at least approximately 25% of an outletcross-sectional area of the tubular arrangement is arranged above thetailwater level. The turbine system may be arranged in an operatingposition relative to a tailwater level such that at least approximately50% of an outlet cross-sectional area of the tubular arrangement isarranged above the tailwater level. The turbine system may be arrangedin an operating position relative to a tailwater level such that atleast approximately 75% of an outlet cross-sectional area of the tubulararrangement is arranged above the tailwater level. The turbine systemmay be arranged in an operating position relative to a tailwater levelsuch that at least approximately 100% of an outlet cross-sectional areaof the tubular arrangement is arranged above the tailwater level.

The invention also provides for a turbine-generator unit comprising theturbine system described above and a generator driven by the turbine,wherein the turbine-generator unit is configured to operate in anenvironment wherein one of there is no liquid level and a liquid leveldownstream of the turbine-generator unit is a low liquid level.

The invention also provides for a turbine-generator module comprising aplurality of turbine-generator units of the type described above,wherein the plurality of turbine-generator units is arranged one of nextto each other and one above another, and wherein the turbine-generatormodule is configured to operate in an environment wherein one of thereis no liquid level and a liquid level downstream of theturbine-generator module is a low liquid level.

The tubular arrangements of the turbine-generator units may be arrangedin a row next to one another, whereby each of the tubular arrangementsopen out at least partially into the open air.

The turbine-generator module may further comprise a closure deviceconfigured to close off at least one of the turbine-generator units sothat liquid cannot flow therethrough.

The invention also provides for a turbine-generator module comprising aplurality of turbine-generator units arranged one of next to each otherand one above another, each turbine-generator unit comprising a turbineand a generator driven by the turbine, at least one tubular arrangementcomprising an opening region, the at least one tubular arrangement beingconnected to at least two of the plurality of turbine-generator units,and a flow arrangement that at least partially prevents a fluid flowfrom becoming detached from the at least one tubular arrangement,wherein the flow arrangement is positioned within the fluid flow and inan area of the opening region.

The invention also provides for a turbine-generator module of the typedescribed above and which further comprises a closure device configuredto close off at least one of the turbine-generator units so that liquidcannot flow therethrough.

The invention also provides for a method of generating electrical energywith the turbine system of the type described above, wherein the methodcomprises arranging the turbine system in a dam installation and causingrotation the turbine.

The dam installation may comprise one of a weir installation and a lock.

The invention also provides for a method of generating electrical energywith the turbine system of the type described above wherein the methodcomprises arranging the turbine system in an existing dam installationand causing rotation the turbine.

The invention also provides for a method of generating electrical energywith the turbine-generator module of the type described above whereinthe method comprises arranging the turbine-generator module between twostationary structures in a dam installation and causing rotation theturbines.

The method may further comprise at least one of raising and lowering theturbine-generator module with a lifting device.

The invention also provides for a method for operating a turbine systemwherein the method comprises connecting a tubular arrangement to adownstream end of a turbine, causing a fluid flow through the tubulararrangement, maintaining the fluid flow within the tubular arrangementat least partially above a tailwater level immediately following thetubular arrangement, positioning a flow arrangement within the fluidflow and in an area of an opening region of the tubular arrangement, andat least partially preventing, with the flow arrangement, the fluid flowfrom becoming detached from the tubular arrangement.

The method may further comprise maintaining the fluid flow immediatelydownstream of the tubular arrangement at least approximately 10% abovethe tailwater level.

The method may further comprise maintaining the fluid flow immediatelydownstream of the tubular arrangement at least approximately 50% abovethe tailwater level.

The method may further comprise maintaining the fluid flow immediatelydownstream of the tubular arrangement at least approximately 100% abovethe tailwater level.

The method may further comprise maintaining the fluid flow immediatelydownstream of the tubular arrangement at least approximately 300% abovethe tailwater level.

The method may further comprise maintaining the fluid flow immediatelydownstream of the tubular arrangement at least approximately 500% abovethe tailwater level.

The invention also provides for a method for operating a turbine system,wherein the method comprises arranging a tubular arrangement on adownstream end of a turbine, causing a fluid flow through the tubulararrangement, maintaining at least a top edge of the tubular arrangementabove a tailwater level that follows an opening region of the tubulararrangement, positioning a flow arrangement within the fluid flow and inan area of the opening region, and at least partially preventing, withthe flow arrangement, the fluid flow from becoming detached from thetubular arrangement.

The invention also provides for a method for generating electricalenergy with a turbine-generator unit, wherein the method comprisescausing a fluid flow through a tubular arrangement of theturbine-generator unit, maintaining at least a top edge of the tubulararrangement above a tailwater level that follows an opening region ofthe tubular arrangement, positioning a flow arrangement within the fluidflow and in an area of the opening region, and at least partiallypreventing, with the flow arrangement, the fluid flow from becomingdetached from the tubular arrangement.

The invention also provides for a method of converting a structure whichretains a liquid medium into a structure which also generates electricalenergy, wherein the method comprises determination a first level of theliquid medium downstream of the structure, determination a second levelof the liquid medium upstream of the structure, the second level beinghigher than the first level, arranging at least one turbine-generatormodule in an area of the structure, wherein the at least oneturbine-generator module comprises a plurality of turbine-generatorunits arranged at least one of next to each other and above one another,each of the turbine-generator units comprising a generator, a turbine,and a tube connected to a downstream end of the turbine, matching, topredetermined levels, a design and efficiency of at least one of theturbines and the generators, maintaining a flow of the liquid medium, atleast in sections, immediately downstream of the tubes such that theflow is at least partially above the first level, positioning a flowarrangement within the flow and in an area of an opening region of eachof the tubes, and at least partially preventing, with each flowarrangement, the flow from becoming detached from the tubes.

The invention also provides for a method of generating electrical energyat a structure which retains a liquid medium, wherein the methodcomprises arranging at least one turbine-generator module in an area ofthe structure, wherein the at least one turbine-generator modulecomprises a plurality of turbine-generator units arranged at least oneof next to each other and above one another, each of theturbine-generator units comprising a generator, a turbine, and a tubeconnected to a downstream end of the turbine, operating theturbine-generator module by allowing a flow of the liquid medium throughthe turbines, positioning a flow arrangement within the flow and in anarea of an opening region of each of the tubes, at least partiallypreventing, with each flow arrangement, the flow from becoming detachedfrom the tubes, and transmitting electrical energy from each generatorto a power supply network.

The invention also provides for a turbine system comprising a turbineand a tubular arrangement comprising an exit opening. The tubulararrangement is arranged on a downstream side of the turbine. At leastone flow controlling rib at least partially prevents a fluid flowthrough the tubular arrangement from becoming detached from the tubulararrangement. The at least one flow controlling rib is positioned withinthe fluid flow and in an area of the exit opening. The turbine system isconfigured to operate efficiently in an environment wherein at least anupper edge of the exit opening is arranged above a downstream liquidlevel.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed descriptionwhich follows, in reference to the noted plurality of drawings by way ofnon-limiting exemplary embodiments of the present invention, in whichlike reference numerals represent similar parts throughout the severalviews of the drawings, and wherein:

FIGS. 1, 1A, 2, 2A, 3, 3A, 4 and 4A show a front view (FIGS. 1-4) and aside view (FIGS. 1A-4A) of a turbine-generator unit with suction tube ina number of design variants;

FIG. 5 shows an example of a dam installation having a turbine-generatormodule;

FIG. 6 FIGS. 6 and 6A show a front view and a side view respectively ofa design variant of the turbine-generator unit with an external flowbody; and

FIGS. 7 and 7A show a front view and side view respectively of a designvariant without an independent tube.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the embodiments of the present invention onlyand are presented in the cause of providing what is believed to be themost useful and readily understood description of the principles andconceptual aspects of the present invention. In this regard, no attemptis made to show structural details of the present invention in moredetail than is necessary for the fundamental understanding of thepresent invention, the description is taken with the drawings makingapparent to those skilled in the art how the forms of the presentinvention may be embodied in practice.

FIGS. 1 and 1A show a turbine-generator unit 1 in its operatingposition, having a generator 2 and a turbine 3 which drives thegenerator 2. The flow through the turbine-generator unit 1 is indicatedby the two arrows. A divergent suction tube 4, which opens out into atailwater. UW, is connected in a known manner to the turbine-generatorunit 1. In this example, however, the tailwater level UW is below thetop edge of the suction-tube opening M, and accordingly, in the state inwhich there is no medium flowing through it, the suction tube 4 opensout partially into the open air. In order now to prevent the dischargejet 7 from becoming detached from the suction tube 4, as indicated bythe dashed line, which, as is known, would considerably reduce theefficiency of the turbine-generator unit 1, an arrangement forpreventing the flow in the suction tube 4 from becoming detached, in theform of a horizontal rib 5, is arranged in the opening region of thesuction tube 4. As can be seen from the side view in FIG. 1A, the rib 5in this case extends over the entire width of the suction tube 4. As aresult, the discharge jet 7 is discharged over the entire cross sectionof the suction tube 4, even though the opening region of the suctiontube 4 is not completely covered by the tailwater UW, as is required inconventional arrangements.

As an alternative to a suction tube 4 as shown in FIG. 1, which ischaracterized by a divergent change in cross section, it is alsopossible to use a simple tube of any desired cross section. Arrangementsof this type are well known and it is therefore also known that inarrangements of this type a lower efficiency has to be accepted from theoutset. Experience has shown that with divergent suction tubes hydraulicefficiencies of approximately >80% can be achieved, whereas with simpletubes efficiencies of typically approximately <60% can be achieved.

In the context of the present invention, the term tube is to beunderstood as meaning any formation of any length with a cavity whosecross section and/or shape is constant or variable and which includes atleast one inlet opening and at least one outlet opening.

Of course, the flow bodies according to the invention are also equallysuitable for turbines with tubes connected downstream, such as forexample suction tubes, without generators. For example, these can beused in installations where the turbines drive a generator arrangedelsewhere via suitable arrangements.

FIGS. 2 and 2A now show the same turbine-generator unit 1 with suctiontube 4 as that shown in FIG. 1. However, in this example the dischargejet 7 sprays out completely into the open air, i.e., in the operatingposition the tailwater level UW is below the bottom edge of thesuction-tube opening M. In extreme cases, there would even be no liquidlevel at all downstream of the turbine or tube. In order, once again, toprevent the flow from becoming detached, with all its negativeconsequences, in this exemplary embodiment there are two horizontal ribs5, arranged one above the other. These devices constitute flow bodies.However, in this case, they do not extend over the entire width of thesuction tube 4. By way of example, the ribs 5 can be arranged in such away that the relationship , where “v” is the flow velocity, “g” is theacceleration due to gravity, and “h” is the distance between the tworibs, is satisfied. Moreover, in this case one of the ribs 5 (e.g., theupper rib) is additionally in part also arranged inclined with respectto the flow passing through the suction tube 4, which likewise improvesthe efficiency of the ribs 5.

FIGS. 3 and 3A show a further exemplary embodiment of aturbine-generator unit 1. In this case, the suction tube 4 changes froma round cross section in the turbine region into a rectangular or, as inthis case, square-shaped suction-tube opening M, as is generally thecase in practice. In this example, the rib 5 is arranged generallyvertically.

Of course, the ribs 5 can be in any desired arrangement and can ofcourse also be of any desired form. For example, they may be in the formof an airfoil or a simple cuboidal shape, provided that the desiredeffect, namely that of preventing the flow from becoming detached in thesuction tube, is achieved as a result. Of course, the ribs 5, can bearranged in a rotated and/or an angular orientation through any desiredangle about the longitudinal axis of the turbine-generator unit 1. Theycan, for example, be diagonally arranged ribs 5. The arrangement canalso be any desired mixture of horizontal, vertical and rotated and/orangled ribs 5. These ribs may, of course, also be of any desired length,they may extend over part or all of the width of the suction tube 4, andif necessary, as shown in, e.g., FIG. 2, may also be positioned at aninclination.

FIGS. 4 and 4A now show a further possible way of preventing the flow inthe suction tube 4 from becoming detached. In this example, thedivergence of the suction tube 4 of the turbine-generator unit 1 isproduced only by the change in cross section over the length of thesuction tube 4. In this case, the round cross section in the turbineregion merges into a square cross-section at the suction-tube opening M.The side length of the square can correspond to the diameter of thesuction tube 4 in the turbine region, which can correspond to the mostcompact arrangement of a turbine-generator unit 1 with suction tube 4.The flow body provided in this case is a concentrically arranged,pear-shaped body 6 in the opening region of the suction tube 4. The body6 is held in the suction tube by two supporting blades 8. However, thesupporting blades 8 could also be designed as ribs 5 as shown in theembodiments illustrated in FIGS. 1, 1A, 2, 2A, 3 and 3A, so that theyalso, at the same time, function as an additional flow body.

The required axial extent of the flow bodies is substantially dependenton the divergence or length of the tube, on the flow velocity of theliquid medium, on the height of the tailwater level UW or the leveldifference between the top water and tailwater UW, and can be adapted tomatch the specific conditions. However, practical tests have shown thatflow bodies in the region of the opening, i.e. approximately in thefinal third of the tube, are sufficient.

It will be clear that it is impossible to list all the possibleembodiments and combinations of suitable flow bodies in the openingregion of the tube. What is essential for the invention, as is clearfrom the description, is the effect of these flow bodies rather thantheir precise configuration. In particular, the present inventionencompasses all possible embodiments of flow bodies of this type.

FIG. 5 shows part of a dam installation 12 having a number of stationarystructures, in this case piers 11. Arranged between the piers 11 is aturbine-generator module 9. The module 9 includes a number ofturbine-generator units 1 arranged next to and/or above one another withlongitudinal axes which are slightly inclined with respect to thehorizontal. A turbine-generator module 9 of this type may also bearranged in such a manner that it can be raised and lowered, in whichcase a lifting device, e.g. a crane, which is not shown, may be providedin order to raise and lower the module. The turbine-generator module 9may also be guided in a guide 14, which is only generally indicated inthe figure. The dam installation 12 shown here also has a rotatablymounted weir gate 10 which can be closed if necessary. This can occur,for example, in situations in which the turbine-generator module 9 isbeing raised.

The dam installation 12 is generally used to maintain a certain topwater level OW. The tailwater level UW can either be a natural result orcan also be controllable.

In the example shown in FIG. 5, the weir crest 13 of the daminstallation 12 is so high that the suction tubes 4 of the upper row ofthe turbine-generator units 1, in their operating position, spraypartially into the open air, and in this example the tubes of the upperrow of the turbine-generator units 1 do not open out completely into thetailwater UW, as indicated by the dashed line. By using a flow body asdescribed in FIG. 1 to 4, these turbine-generator units 1 can now alsobe used in dam installations 12 of this type, which would hitherto haveonly been possible with in some cases very considerable losses inefficiency.

Furthermore, the turbine-generator module 9 may comprise closure devices(not shown here), by way of which some and/or all of theturbine-generator units 1 can be closed off so that the liquid cannotflow through the turbine-generator units 1. This situation could arise,for example, if the top water level OW becomes too low and the dammingfunction of the dam installation can no longer be ensured. In this case,the turbine-generator module 9 can be raised out of the waterway for,e.g., maintenance or in the event of a flood or in order to control thequantitative flow.

A situation of this nature, in which the tailwater level UW is very lowor absent altogether, may arise in particular in existing daminstallations 12 which have hitherto only been used to maintain apredetermined liquid level and are now also to be used to generateelectrical energy. Hitherto, converting dam installations 12 of thistype into installations for generating electrical energy has beenimpossible or has involved very considerable levels of outlay, sinceconventional tubes, such as for example suction tubes 4, which spraycompletely or partially into the open air would mean a considerable lossof efficiency. This would in turn make the installation uneconomical. Byusing the flow bodies according to the invention it is now possible forthe first time for even existing dam installations 12 of this type to beconverted into installations for generating electrical energy with anacceptable level of outlay.

For this purpose, by way of example, closure members which are presentbetween two piers 11 are replaced by a turbine-generator module 9 asillustrated for example in FIG. 5. The turbine-generator module 9 can bematched to the predetermined levels and the existing structures of thedam installation 12, so that an optimum efficiency can be achieved. Thesuction tubes 4 of the turbine-generator units 1, which open out atleast partially into the open air, are equipped with flow bodiesaccording to the invention, so that the flow does not become detached inthe opening region of the suction tubes 4, and full efficiency of thesystem can be exploited.

FIGS. 6 and 6A also show a further possible exemplary embodiment of aturbine-generator unit 1 with a generator 2 and a turbine 3, to which ashort suction tube 4 is connected. In this case, an arrangement forpreventing the flow in the suction tube 4 from becoming detached isarranged directly downstream of the suction tube 4, as seen in thedirection of flow. In this specific example, this arrangement comprisesa horizontal rib 5, which is held in the flow of the discharge jet 7 bya supporting construction or arrangement 15. This example shows, inparticular, that the arrangement does not necessarily have to bearranged in the suction tube 4 or tube, but rather, may also be locatedoutside it and/or separated therefrom.

In the examples shown in FIGS. 1, 1A, 2, 2A, 3, 3A, 4, 4A, 5, 6 and 6A,the turbine housing, in which the turbine 3 runs, and the tube connectedto the turbine 3 are separate components which, as indicated in theFigures, are connected to one another. This can occur, for example, byway of a flanged connection. It can now be seen from FIGS. 7 and 7A thatthe tube does not necessarily have to be an independent component, butrather, it is also possible for the turbine housing 16 to be widenedinto the shape of a tube at the downstream end, and of course also intothe shape of a suction tube, so that it fulfills the same function as aseparate, connected tube. Of course, as described above, it is thenpossible for an arrangement for preventing the flow in the tubularwidening from becoming detached. This can, for example, take the form oftwo ribs 5 which are rotated and/or angularly oriented with respect tothe horizontal or vertical, and can be arranged in the tubular wideningportion of the turbine housing.

Even if the exemplary embodiments only show variants with divergenttubes or tubes with a constant cross section, other tubes, such as forexample a convergent tube (i.e., a tube with a decrease in crosssection) or an alternately divergent, convergent or constant tube, arealso, of course, conceivable.

It is noted that the foregoing examples have been provided merely forthe purpose of explanation and are in no way to be construed as limitingof the present invention. While the present invention has been describedwith reference to an exemplary embodiment, it is understood that thewords that have been used are words of description and illustration,rather than words of limitation. Changes may be made, within the purviewof the appended claims, as presently stated and as amended, withoutdeparting from the scope and spirit of the present invention in itsaspects. Although the invention has been described herein with referenceto particular means, materials and embodiments, the invention is notintended to be limited to the particulars disclosed herein. Instead, theinvention extends to all functionally equivalent structures, methods anduses, such as are within the scope of the appended claims.

1. An apparatus comprising: a plurality of turbine-generator modules,wherein each module includes: a generator; a turbine system operable inat least one of an environment in which there is a low liquid level andan environment wherein there is no liquid level downstream of a turbine,the turbine system further comprising: a turbine; a tubular arrangementcomprising an opening region; the tubular arrangement being connected toa downstream side of the turbine; a flow arrangement that at leastpartially prevents a fluid flow from becoming detached from the tubulararrangement; and the flow arrangement being positioned within the fluidflow and in an area of the opening region wherein, when no medium isflowing through the turbine system, the turbine system is arranged in anoperating position relative to a tailwater level such that at leastapproximately 10% of an outlet cross-sectional area of the tubulararrangement is arranged above the tailwater level, and a closure deviceadjacent at least one of said modules, wherein the closure deviceincludes an operating position to close off at least one of theturbine-generator modules to prevent liquid flowing therethrough.
 2. Theapparatus of claim 1 wherein the tubular arrangement is a suction tube.3. The apparatus of claim 1 wherein an axis of rotation of the turbineis arranged as one of substantially horizontally and inclined withrespect to a horizontal reference.
 4. The apparatus of claim 1 whereinthe turbine further comprises a turbine rotor having a plurality ofturbine blades rigidly arranged on a rotor shaft.
 5. The apparatus ofclaim 1 wherein the flow arrangement comprises a flow body.
 6. Theapparatus of claim 5 wherein the tubular arrangement comprises a tubeand wherein the flow body is arranged in the tube and in an area of adownstream end of the tube.
 7. The apparatus of claim 1 wherein the flowarrangement comprises at least one rib.
 8. The apparatus of claim 7wherein the at least one rib is arranged substantially horizontally. 9.The apparatus of claim 1 wherein the flow arrangement comprises at leastone flow body arranged substantially vertically.
 10. The apparatus ofclaim 1 wherein the flow arrangement comprises at least one flow bodyarranged at an inclined with respect to one of a horizontal plane and avertical plane.
 11. A turbine-generator module comprising: a pluralityof turbine-generator units arranged in an array having at least one unitabove another unit; each turbine-generator unit further comprising aturbine and a generator driven by the turbine; at least one tubulararrangement comprising an opening region, the at least one tubulararrangement being connected to at least two of the plurality ofturbine-generator units; and a flow arrangement that at least partiallyprevents a fluid flow detaching from the at least one tubulararrangement, wherein the flow arrangement is positioned within the fluidflow and in an area of the opening region.
 12. The turbine-generatormodule of claim 11 further comprising a closure device configured toclose off at least one of the turbine-generator units so that liquidcannot flow therethrough.
 13. The turbine-generator module of claim 11wherein the flow arrangement comprises at least one rib inclined withrespect to the fluid flow.
 14. The turbine-generator module of claim 11wherein the flow arrangement comprises at least one pear-shaped bodyarranged concentrically in the tubular arrangement.
 15. Theturbine-generator module of claim 14 wherein the at least onepear-shaped body is supported in the tubular arrangement by a pluralityof support blades.
 16. The turbine-generator module of claim 11 whereinthe tubular arrangement at least partially opens to open air.
 17. Theturbine-generator module of claim 11 wherein, when no medium is flowingthrough the turbine system, the turbine system is arranged in anoperating position relative to a tailwater level such that at leastapproximately 25% of an outlet cross-sectional area of the tubulararrangement is arranged above the tailwater level.
 18. Theturbine-generator module of claim 11 wherein, when no medium is flowingthrough the turbine system, the turbine system is arranged in anoperating position relative to a tailwater level such that at leastapproximately 50% of an outlet cross-sectional area of the tubulararrangement is arranged above the tailwater level.
 19. Theturbine-generator module of claim 11 wherein, when no medium is flowingthrough the turbine system, the turbine system is arranged in anoperating position relative to a tailwater level such that at leastapproximately 75% of an outlet cross-sectional area of the tubulararrangement is arranged above the tailwater level.
 20. Theturbine-generator module of claim 11 wherein, when no medium is flowingthrough the turbine system, the turbine system is arranged in anoperating position relative to a tailwater level such that an entiretyof an outlet cross-sectional area of the tubular arrangement is arrangedabove the tailwater level.